Islamabad, Pakistan (CNN) -- An earthquake with a magnitude of 7.2 struck Wednesday morning in a remote area of southwestern Pakistan, but initial reports revealed no major damage.

The earthquake occurred at 1:23 a.m. (3:23 p.m. Tuesday ET) at a depth of 84 kilometers (52 miles), the U.S. Geological Survey said. It was centered 45 kilometers (30 miles) west of Dalbandin, and 1,035 kilometers (640 miles) west-southwest of Islamabad, the USGS said on its website.

Arif Mahmood, director of the Pakistan Meteorological Department, put the epicenter at 320 kilometers (about 200 miles) southwest of Quetta near Kharan, Balochistan, and said it had been felt in Punjab, Sindh, and Balochistan provinces in Pakistan, as well as parts of Iran and India.

Mahmood predicted major aftershocks. "Earthquakes with such magnitudes in the past have brought on aftershocks," he told CNN from Islamabad.

Residents near the epicenter in the districts of Kalat, Dalbadin and Kharan told CNN some mud-walled homes were damaged but no one was hurt.

An official at Quetta's Civil Hospital said a female cardiac patient suffered a fatal heart attack during the earthquake. He said two residents raced to the hospital but they proved not to have been injured, just scared.

Pakistan rocked by earthquake

Malik Muhammad Iqbal, the police chief of Balochistan province, said he was aware of no injuries.

"Things in the headquarters started shaking and books fell off the desks," Balochistan Police Inspector Sultan Mehmood told CNN in a telephone interview. "We left the headquarters running into the streets -- scared for our lives."

In Karachi, Faraz Leghari, director general police, said he had heard no immediate reports of casualties or building damage.

USGS initially reported the quake at 7.4. Quakes of 7.0 to 7.9 are classified as major; anything over 8.0 is classified as great.

In Dubai, about 500 miles southwest of the epicenter, a reporter said he felt a moderate shaking that lasted for about 30 seconds.

Usman Zahid, a night manager at Serina Hotel in Quetta, Pakistan, felt the quake. He said it was "frightening" and estimated that it lasted about 20 seconds. It left "broken glass in the kitchen" and made a chandelier swing, but caused no major damage, he said.

People with Twitter accounts in New Delhi, Jaipur and Dehradun -- all in India -- felt the quake. People with Twitter accounts in Bahrain said they felt the quake.

In Dubai, "I was just getting ready to go to bed," said Leone Lakhani in Dubai. She said she texted her friends in Abu Dhabi and Bahrain.

"It's not uncommon for this region to have earthquakes," said Kurt Frankel of the Georgia Institute of Technology. It is where two tectonic plates come together, he said.